3 files changed, 106 insertions, 0 deletions
diff --git a/clang/test/ASTMerge/namespace/Inputs/namespace1.cpp b/clang/test/ASTMerge/namespace/Inputs/namespace1.cpp
new file mode 100644
index 00000000000..4a539523aae
--- /dev/null
+++ b/clang/test/ASTMerge/namespace/Inputs/namespace1.cpp
@@ -0,0 +1,27 @@
+// Merge success
+namespace N1 {
+  int x;
+}
+
+// Merge multiple namespaces
+namespace N2 {
+  extern int x;
+}
+namespace N2 {
+  extern float y;
+}
+
+// Merge namespace with conflict
+namespace N3 {
+  extern float z;
+}
+
+namespace AliasWithSameName = N3;
+
+namespace TestUnresolvedTypenameAndValueDecls {
+template <class T> class Base {
+public:
+  typedef T foo;
+  void bar();
+};
+}
diff --git a/clang/test/ASTMerge/namespace/Inputs/namespace2.cpp b/clang/test/ASTMerge/namespace/Inputs/namespace2.cpp
new file mode 100644
index 00000000000..f65057d1ca6
--- /dev/null
+++ b/clang/test/ASTMerge/namespace/Inputs/namespace2.cpp
@@ -0,0 +1,60 @@
+// Merge success
+namespace N1 {
+  extern int x0;
+}
+
+// Merge multiple namespaces
+namespace N2 {
+  extern int x;
+}
+namespace N2 {
+  extern float y;
+}
+
+// Merge namespace with conflict
+namespace N3 {
+  extern double z;
+}
+
+namespace Enclosing {
+namespace Nested {
+  const int z = 4;
+}
+}
+
+namespace ContainsInline {
+  inline namespace Inline {
+    const int z = 10;
+  }
+}
+
+namespace TestAliasName = Enclosing::Nested;
+// NOTE: There is no warning on this alias.
+namespace AliasWithSameName = Enclosing::Nested;
+
+namespace TestUsingDecls {
+
+namespace A {
+void foo();
+}
+namespace B {
+using A::foo; // <- a UsingDecl creating a UsingShadow
+}
+
+}// end namespace TestUsingDecls
+
+namespace TestUnresolvedTypenameAndValueDecls {
+
+template <class T> class Base;
+template <class T> class Derived : public Base<T> {
+public:
+  using typename Base<T>::foo;
+  using Base<T>::bar;
+  typedef typename Derived::foo NewUnresolvedUsingType;
+};
+
+} // end namespace TestUnresolvedTypenameAndValueDecls
+
+namespace TestUsingNamespace {
+  using namespace Enclosing;
+}
diff --git a/clang/test/ASTMerge/namespace/test.cpp b/clang/test/ASTMerge/namespace/test.cpp
new file mode 100644
index 00000000000..f0f8b73ffcb
--- /dev/null
+++ b/clang/test/ASTMerge/namespace/test.cpp
@@ -0,0 +1,19 @@
+// FIXME: Errors are now warnings.
+// XFAIL: *
+// RUN: %clang_cc1 -emit-pch -std=c++1z -o %t.1.ast %S/Inputs/namespace1.cpp
+// RUN: %clang_cc1 -emit-pch -std=c++1z -o %t.2.ast %S/Inputs/namespace2.cpp
+// RUN: not %clang_cc1 -std=c++1z -ast-merge %t.1.ast -ast-merge %t.2.ast -fsyntax-only %s 2>&1 | FileCheck %s
+
+static_assert(TestAliasName::z == 4);
+static_assert(ContainsInline::z == 10);
+
+void testImport() {
+  typedef TestUnresolvedTypenameAndValueDecls::Derived<int> Imported;
+  Imported a; // Successful instantiation
+  static_assert(sizeof(Imported::foo) == sizeof(int));
+  static_assert(sizeof(TestUnresolvedTypenameAndValueDecls::Derived<double>::NewUnresolvedUsingType) == sizeof(double));
+}
+
+
+// CHECK: namespace2.cpp:16:17: error: external variable 'z' declared with incompatible types in different translation units ('double' vs. 'float')
+// CHECK: namespace1.cpp:16:16: note: declared here with type 'float'